The ability to rapidly identify and clone genes of interest, synthesize cRNA probes, and resolve regional and cellular expression has facilitated current understanding of cellular diversity in the brain, as well as appreciation of relationships between mutations, gene expression, and aberrant phenotypes. In parallel, quantitative PCR has emerged as a complimentary method to assess variation in levels as well as patterns of expression. These two methods provide a necessary transition from molecular discovery-based approaches such as expression microarray to hypothesis-driven experiments to understand gene function in the brain. The integration of expression analysis with other Core services described in this proposal facilitates the most difficult step in molecular and genetic analyses of CMS development or function: translation of molecular data into cell biological and systemic insight. The expansion of Core 2 services to include quantitative PCR as well as a well-developed library of validated probe templates will help insure the high level of productivity maintained by NINDS-supported investigators who accessed and used core services in the past 4 years.